What Causes Goldfish Fin Rot?

Goldfish fin rot primarily occurs due to bacterial infection, but it can also occur due to fungal infection. It causes the fins to fray and look ragged. Usually, the fin rot begins at the edges and gradually moves towards the base of the fin. If treatment is given before the rot reaches the body, the goldfish can regenerate the fins. On the other hand, untreated goldfish fin rot causes the infection to spread to the rest of the body.

  1. Goldfish Fin Rot Causes

    • The bacteria responsible for fin rot in goldfish are usually present in aquariums. However, even stress, overcrowding, injury and poor-quality water can cause it. When the aquarium water has high pH, nitrates or ammonia, it can erode the goldfish's fins.

    What Goldfish Fin Rot Looks Like

    • Typically, the edges of the fins appear discolored and the discoloration can be lighter or darker than the color of the goldfish. When bacteria cause the fin rot, the fins look frayed, with pink edges and red streaks. On the other hand, fungal infection causes the fins to fray evenly and they have white edges. When goldfish fin rot occurs due to presence of chemicals in the aquarium water, the edges of the fins do not appear furry and ragged.

    Treating Fin Rot

    • Remove 25 to 30 percent of the water in the aquarium and add fresh water. Agitate the water before removing it, so fish waste and decaying food particles are more or less removed from the aquarium. Treat the water with chlorine remover. Add some aquarium salt. You can use table salt, as long as it is not iodized. Iodized salt is toxic to goldfish. The salt prevents bacteria and fungi from proliferating in the aquarium. Add around 1 tbsp. of salt for every 5 gallons of water. While the salt prevents the pathogens from multiplying, it does not cure the fin rot. Consult your vet about a suitable antibiotic for your goldfish. Also, do not forget to clean the algae growing on the sides of the aquarium carefully.

    Preventing Fin Rot

    • Refrain from overcrowding the aquarium and overfeeding the goldfish. Uneaten food particles get deposited on the substrate and are excellent breeding ground for bacteria and fungi. Just feed the goldfish how much it can eat in 5 minutes. Do not house your goldfish with fish that tend to bite fins of other fish. Change the water in the aquarium partially at least twice a week.